This invention relates to a process for the production of certain alkali metal silicoformic cyanides by chemically reacting silicoformic acid (H.Si0.OH) with a suitable cyanide compound in a ratio of about 1:1 or 1:2 mols.
The silicoformic acid may be produced by the chemical reaction of a dry alkaline earth metal metasilicate or a dry alkali metal metasilicate with a mineral acid or a hydrogen containing acid salt. The silicoformic acid produced is washed with water, filtered and air dried to a granular white powder. Silicoformic acid, also known as monosilanic acid, may also be produced by other methods, such as those disclosed in U.S. Pat Nos. 3,674,430, 3,929,972, 3,954,941 and 3,962,067.
The silicoformic acid used in the following examples was produced by reacting dry granular alkali metal metasilicate with an hydrogen containing acid salt or a concentrated mineral acid. The white granules of silicoformic acid were washed with water, filtered, and then air dried at 25.degree. to 75.degree. C. The silicoformic acid granules were analyzed by Infrared analysis, using the 1R KBr disc method.
The Infrared analysis showed the presences of Si--H bonds. The Infrared analysis was very similar to that obtained with Mallinckrodt's hydrated silica except for the area which shows the presence of Si--H bonds. The Mallinckrodts hydrated silica (SiO.sub.2..sub. x H.sub.2 O) has a molecular weight of 60.09.sup...sub. x H.sub.2 O. The silicoformic acid produced contains an active hydrogen which will reduce silver nitrate in an aqueous solution which is evidence that Si-H bonds are present.
When the said silicoformic acid is heated much above 105.degree. C., silicon dioxide with a molecular weight of about 60 is produced. On further heating, it has a melting point of 1650.degree. C. In Cryoscopic and ebullioscopic determination, the silicoformic acid produced was not soluble in any common organic solvent but was readily soluble in dilute alkali metal hydroxide aqueous solutions.
The molecular weight was determined from the boiling point elevation of the said silicoformic acid in a 6N sodium hydroxide solution and indicated a molecular weight of 78.+-. 25gm/mol. This type of reactive solution normally changes the molecular species. However, this would seem to indicate the absence of a polymeric form of silicate. This analysis may indicate a possible formula of HSi(OH).sub.3 (orthosilicoformic acid) and the presence of some metasilicic acid (H.sub.2 SiO.sub. 3). The Orthosilicoformic acid, when dried, will lose water to form silicoformic acid. Other silicoformic acid such as polysilicoformic acid and orthosilicoformic acid may be used in my process.
The various alkali silico-formic cyanide compounds produced are useful as an intermediate in the production of many silicoformic organic compounds, such as silicoformic amines, silicoformic isocyanates, silicoformic organic acids, silicoformic cyanides, silicoformic organic esters and other silico organic compounds.